Deformation of the Earth's crust by glacial loading and unloading was first recognized more than a century ago (De Geer 1888). This deformation is expressed by postglacial isostatic rebound and is ongoing in large parts of glaciated regions. It is typically a process with uplift rates of millimetres per year (Johansson et al. 2002). The crustal rebound which initially followed deglaciation was, however, faster and therefore caused large earthquakes under certain conditions (Lundqvist & Lagerbäck 1976; Steffen et al. 2014). In Lake Vättern, southern Sweden, mass wasting and deformation structures have been mapped in the sediment accumulated on the lake floor (Jakobsson et al. 2014). Along an 80 km stretch of the lake, deformation structures seen in sediments reveal up to 13 m of vertical displacement in the underlying bedrock. From this displacement, an earthquake with seismic magnitude up to 7.5 was interpreted to have occurred in Lake Vättern shortly after the Scandinavian Ice Sheet had retreated …